altitudeMonotonic property
This altitude measure is initialized on system boot and monotonic (it is never reset, but represents the local altitude change). The only guarantee on this field is that it will never be reset and is consistent within a flight. The recommended value for this field is the uncorrected barometric altitude at boot time. This altitude will also drift and vary between flights.
MAVLink type: float
units: m
altitude_monotonic
Implementation
final float altitudeMonotonic;